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Korek M.J.,Karolinska Institutet | Bellander T.D.,Karolinska Institutet | Bellander T.D.,Center for Occupational and Environmental Medicine | Lind T.,Center for Occupational and Environmental Medicine | And 14 more authors.
Journal of Exposure Science and Environmental Epidemiology

We investigated the risk of stroke related to long-term ambient air pollution exposure, in particular the role of various exposure time windows, using four cohorts from Stockholm County, Sweden. In total, 22,587 individuals were recruited from 1992 to 2004 and followed until 2011. Yearly air pollution levels resulting from local road traffic emissions were assessed at participant residences using dispersion models for particulate matter (PM10) and nitrogen oxides (NOX). Cohort-specific hazard ratios were estimated for time-weighted air pollution exposure during different time windows and the incidence of stroke, adjusted for common risk factors, and then meta-analysed. Overall, 868 subjects suffered a non-fatal or fatal stroke during 238,731 person-years of follow-up. An increment of 20 μg/m3 in estimated annual mean of road-traffic related NOX exposure at recruitment was associated with a hazard ratio of 1.16 (95% CI 0.83-1.61), with evidence of heterogeneity between the cohorts. For PM10, an increment of 10 μg/m3 corresponded to a hazard ratio of 1.14 (95% CI 0.68-1.90). Time-window analyses did not reveal any clear induction-latency pattern. In conclusion, we found suggestive evidence of an association between long-term exposure to NOX and PM10 from local traffic and stroke at comparatively low levels of air pollution. © 2015 Nature America, Inc. All rights reserved. Source

Eriksson E.,Technical University of Denmark | Revitt D.M.,Middlesex University | Ledin A.,Lund University | Lundy L.,Middlesex University | And 3 more authors.
Water Science and Technology

Cities of the future face challenges with respect to the quantity and quality of water resources, and multiple managerial options need to be considered in order to safeguard urban surface water quality. In a recently completed project on 'Source control options for reducing emissions of Priority Pollutants' (ScorePP), seven emission control strategies (ECSs) were developed and tested within a semi-hypothetical case city (SHCC) to evaluate their potential to reduce the emission of selected European priority hazardous substances (PHSs) to surface waters. The ECSs included (1) business-as-usual, (2) full implementation of relevant European (EU) directives, (3) ECS2 in combination with voluntary options for household, municipalities and industry, (4) ECS2 combined with industrial treatment and best available technologies (BAT), (5) ECS2 in combination with stormwater and combined sewer overflow treatment, (6) ECS2 in combination with advanced wastewater treatment, and (7) combinations of ECS3-6. The SHCC approach was chosen to facilitate transparency, to allow compensating for data gaps and to decrease the level of uncertainty in the results. The selected PHSs: cadmium (Cd), hexachlorobenzene (HCB), nonylphenol (NP) and pentabromodiphenyl ether (PBDE) differ in their uses and environmental fate and therefore accumulate in surface waters to differing extents in response to the application of alternative ECS. To achieve the required reduction in PHS levels in urban waters the full implementation of existing EU regulation is prioritised and feasible combinations of managerial and technological options (source control and treatment) can be highly relevant for mitigating releases. © IWA Publishing 2011. Source

Oudin A.,Umea University | Carlsen H.K.,University of Iceland | Forsberg B.,University of Stockholm | Johansson C.,Environment and Health Administration
International Journal of Environmental Research and Public Health

In the aftermath of the Icelandic volcano Grimsvötn's eruption on 21 May 2011, volcanic ash reached Northern Europe. Elevated levels of ambient particles (PM) were registered in mid Sweden. The aim of the present study was to investigate if the Grimsvötn eruption had an effect on mortality in Sweden. Based on PM measurements at 16 sites across Sweden, data were classified into an ash exposed data set (Ash area) and an unexposed data set (No ash area). Data on daily all-cause mortality were obtained from Statistics Sweden for the time period 1 April through 31 July 2011. Mortality ratios were calculated as the ratio between the daily number of deaths in the Ash area and the No ash area. The exposure period was defined as the week following the days with elevated particle concentrations, namely 24 May through 31 May. The control period was defined as 1 April through 23 May and 1 June through 31 July. There was no absolute increase in mortality during the exposure period. However, during the exposure period the mean mortality ratio was 2.42 compared with 2.17 during the control period, implying a relatively higher number of deaths in the Ash area than in the No ash area. The differences in ratios were mostly due to a single day, 31 May, and were not statistically significant when tested with a Mann-Whitney non-parametric test (p > 0.3). The statistical power was low with only 8 days in the exposure period (24 May through 31 May). Assuming that the observed relative differences were not due to chance, the results would imply an increase of 128 deaths during the exposure period 24-31 May. If 31 May was excluded, the number of extra deaths was reduced to 20. The results of the present study are contradicting and inconclusive, but may indicate that all-cause mortality was increased by the ash-fall from the Grimsvötn eruption. Meta-analysis or pooled analysis of data from neighboring countries might make it possible to reach sufficient statistical power to study effects of the Grimsvötn ash on morbidity and mortality. Such studies would be of particular importance for European societies preparing for future large scale volcanic eruptions in Iceland. © 2013 by the authors; licensee MDPI, Basel, Switzerland. Source

Olsson D.,Umea University | Mogren I.,Umea University | Eneroth K.,Environment and Health Administration | Forsberg B.,Umea University
BMJ Open

Background: For the past two decades, several studies have reported associations between elevated levels of ambient air pollution and adverse pregnancy outcomes, although with varying conclusions. Objectives: To examine possible associations between the traffic pollution situation at the home address, for women who did not change address during pregnancy, and three types of pregnancy outcomes: spontaneous preterm delivery, children born small for gestational age (SGA) and pregnancy-induced hypertensive disorders. Methods: We used data for the Greater Stockholm Area from the Swedish Medical Birth Register to construct a cohort based on all pregnancies conceived between July 1997 and March 2006, n=100 190. The pregnancy average nitrogen oxide, NOx, levels and annual mean daily vehicles at the home address were used as exposure variables. Mixed-model logistic regression was performed to assess any associations between exposure and outcome. Results: There was an association between elevated traffic pollution exposure during pregnancy and pregnancy-induced hypertensive disorders. A 10 μg/m3 increase in the pregnancy average NOx level at the home address resulted in an OR of 1.17 (95% CI 1.10 to 1.26). The 2nd to 4th quartiles of NOx were all associated with an increased risk of SGA, but there was no difference in the risk estimate among the higher quartiles. There was a tendency of a higher risk of spontaneous preterm delivery in relation to higher levels of NOx. There was no evidence of an association between vehicle flow, the cruder indicator of traffic pollution, and the studied outcomes in this study. Conclusions: In this large cohort, there was a fairly strong association between vehicle exhaust levels at the home address and pregnancy-induced hypertensive disorders, after adjustment for important risk factors. Source

Molgaard B.,University of Helsinki | Birmili W.,Leibniz Institute for Tropospheric Research | Clifford S.,Queensland University of Technology | Massling A.,University of Aarhus | And 8 more authors.
Journal of Aerosol Science

In this study we evaluated a forecast model for urban aerosol number concentrations against measurements made at five European cities: Helsinki, Stockholm, Copenhagen, Leipzig, and Athens. This model requires a learning data set with particle number concentrations, traffic densities and local meteorology. Additionally, in the forecasting process it requires the same parameters from the past week and forecasted values of weather and traffic. The model performance was tested based on the R2, index of agreement (IA), mean square error (MSE), and bias. We tested three modelling approaches: one with fixed parameterisation and two with optimisations based on either the Deviance or the Akaike Information Criterion. Based on the hourly one-day forecasts at the urban background sites the IA ranged from 0.65 to 0.80 for accumulation mode particles and from 0.68 to 0.87 for ultrafine particles. The model performance was the best for Helsinki and Stockholm and the worst for Leipzig and Copenhagen. The main reason is the more pronounced diurnal variation in Helsinki and Stockholm. Another reason is that the traffic data for Leipzig and Copenhagen were not as complete as for the other cities. The three approaches yielded similar model performances, hence we conclude that the simplest one based on a fixed parametrisation is to be preferred. © 2013 Elsevier Ltd. Source

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